Portolan Chart of the Mediterranean

This map, created by Juan Vespucio, or Giovanni Vespucci, was charted according to the Mediterranean template, or padrón, kept at the House of Trade (Casa de Contratación).

The Padrón Real was Spain's official, secret master map, and was used as a template for the maps and nautical charts carried on all Spanish ships during the 16th century. It was created and maintained by the House of Trade with the Indies in Seville. The map was revised throughout the 16th century, with the incorporation of new discoveries and information contributed by the captains of voyages to the New World.

It covers the Mediterranean and European Atlantic Ocean, from Iceland and the southern coast of Scandinavia to The Gambia and Cape Roxo in Africa. Enough of the ocean is included to show the Azores, Madeira, the Canary Islands, and Cape Verde. However, it does not feature any stretch of the South American coast.

There are shields over England, Scotland, and Ireland. The main cities are symbolized by seven identical monuments: red over Tunis, Milan, and Belgrade (potential threats) and green over Jerusalem, Venice, Genoa, Seville, and Morocco.

There are also flags over Turkey, Crimea, and France, as well as Madeira and the Canary Islands.

This portolan chart is an example of the transition from the old to the new era. Juan Vespucio made this chart of the Mediterranean in the traditional portolan style that Mallorcans and Italians had mastered. However, as could be expected of a specialist in new hydrographic techniques, he also introduced the concept of sailing west over the Atlantic.

The two scales of longitude over the Atlantic Ocean could mean that this portolan chart uses the controversial dual-graduation system. This indicated to ship captains that, from the Azores, the needle would start to move northeast, so they would have to correct their course. They therefore used one scale to the Azores, and another beyond, having noted the difference that the needle dipped while sailing to the Americas.